Poor performance on mac with AMD Radeon Pro 560
Actually there is one more thing you should do before trying GPU render, that GREATLY affects the render speed: the size of the render tile. By default, render tile in Blender is fairly small which works well for CPU-based rendering. However GPU renderers work faster with large render tiles, around 512px (default is 64px I think). See this article for details, step 3:
https://www.blenderguru.com/articles/4-easy-ways-to-speed-up-cycles

The tile size parameter:



Comparison tile size vs render speed:


Since I am interested in Macbook Pro performance, can you check the tile size again and post your results?